JP2016150920A - Compound for organic electroluminescent element and organic electroluminescent element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compound for an organic electroluminescent element which allows a sufficiently long driving life to be obtained when used as a constituent material of an organic electroluminescent element, and to provide an organic electroluminescent element using the compound.SOLUTION: The compound for an organic electroluminescent element is an anthracene compound having at least one substituent represented by general formula (2). The organic electroluminescent element uses the compound. (L is a linking group and is a single bond, a substituted/unsubstituted arylene group, a substituted/unsubstituted divalent group having a heterocyclic skeleton, or the like; and R1 and R2 are each independently H, a substituted/unsubstituted alkyl group, or the like.)SELECTED DRAWING: None

Description

  The present invention relates to a compound for an organic electroluminescent device and an organic electroluminescent device using the same.

  The organic electroluminescence device can emit light at a low voltage of about several volts to several tens of volts, and can emit light of various colors by selecting the type of the fluorescent organic compound. Applications to devices, display devices, etc. are expected, and development and research are being actively promoted. In general, an organic electroluminescent element is composed of a light emitting layer and a pair of counter electrodes sandwiching the layer. When an electric field is applied between both electrodes, holes are injected from the hole injection electrode (anode) side, and electrons are injected from the electron injection electrode (cathode) side. Furthermore, holes and electrons recombine in the light emitting layer to generate an excited state, and energy is released as light when the excited state returns to the ground state.

  Conventional organic electroluminescent elements have a higher driving voltage than inorganic light emitting diodes, have low luminance and luminous efficiency, and have not been put into practical use. Improvements have gradually improved the performance of organic electroluminescent devices. Improving the luminous efficiency and extending the life of organic electroluminescent elements are important issues that lead to lower power consumption and improved durability of the light emitting elements and display elements.

  In order to solve these problems, various improvements in materials for organic electroluminescent elements have been made, and compounds having various structures have been proposed. Among them, it is known that a compound having an anthracene structure is excellent as a material for organic electroluminescence devices having a long life and high efficiency. Patent Document 1 describes a highly reliable compound for an organic electroluminescence device having a dianthracene structure. As long-life, high-efficiency compounds for organic electroluminescence devices, Patent Documents 2 and 3 describe asymmetric anthracene derivatives having phenanthrene and pyrene, and Patent Document 4 describes anthracene derivatives having fluorene. .

Japanese Patent No. 4190542 Japanese Patent No. 4041816 Japanese Patent No. 4839351 JP 2002-154993 A

  However, even when these materials are used, the driving life of the organic electroluminescent element is still insufficient, and further life extension is required.

  The present invention has been made in view of the above circumstances, and when used as a constituent material of an organic electroluminescent element, a compound for an organic electroluminescent element capable of obtaining a sufficiently long driving life and an organic material using this compound An object is to provide an electroluminescent device.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by using a compound represented by the following general formula (1) as a material for an organic electroluminescence device. This invention provides the compound for organic electroluminescent elements represented by following General formula (1).

  This invention provides the compound for organic electroluminescent elements represented by following General formula (1).

［式中、Ｘ_１〜Ｘ_１０のうち少なくとも１つは下記一般式（２）で表される。

[Wherein, at least one of X _{1 to} X ₁₀ is represented by the following general formula (2).

（式中、Ｌは連結基であり、位置１〜１４のいずれかの位置と連結する。なお、式中の番号は、連結基Ｌの連結位置を示すための番号である。連結されなかった位置１〜１４は、水素原子、置換または無置換のアルキル基、置換もしくは無置換のアリール基、置換もしくは無置換の複素環基のいずれかで置換される。Ｌは、単結合、置換もしくは無置換のアルキリレン基、置換もしくは無置換のアリーレン基、置換もしくは無置換の複素環骨格を有する２価の基のいずれかを示す。Ｒ_１およびＲ_２は、それぞれ独立に、水素原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアリール基のいずれかを示す。）Ｘ_１〜Ｘ_１０のうち一般式（２）でないものは、それぞれ独立に、水素原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアリール基、置換もしくは無置換の複素環基のいずれかを示す。］

(In the formula, L is a linking group and is linked to any one of positions 1 to 14. The number in the formula is a number for indicating the linking position of the linking group L. Not linked. Positions 1 to 14 are substituted with any of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group, and L is a single bond, substituted or unsubstituted. R ₁ and R ₂ are each independently a hydrogen atom, substituted or unsubstituted, a substituted alkylylene group, a substituted or unsubstituted arylene group, or a divalent group having a substituted or unsubstituted heterocyclic skeleton. A substituted alkyl group or a substituted or unsubstituted aryl group.) Among X _{1 to} X ₁₀ , those not represented by the general formula (2) are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, Place Or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. ]

  According to the compound for an organic electroluminescent element according to the present invention, when it is used as a constituent material of the organic electroluminescent element, a sufficiently long driving life can be obtained. The reason why such an effect is obtained by the compound for organic electroluminescence device according to the present invention is not necessarily clear, but the present inventors consider as follows.

  Highly symmetric molecules easily align with the heat generated by driving or the passage of time, resulting in crystallization of the thin film, so that a sufficiently long driving life can be obtained when used as a material for organic electroluminescent devices. I can't. The compound for organic electroluminescent elements according to the present invention has at least one substituent having a large steric hindrance represented by the general formula (2) on anthracene. As a result, the symmetry of the whole molecule is lowered and the crystallinity is lowered, so that it is possible to produce a stable amorphous film and to obtain a sufficiently long driving life.

  The organic electroluminescent device according to the present invention is an organic electroluminescent device in which at least one organic layer including a luminescent layer is sandwiched between a pair of electrodes composed of an anode and a cathode. It is preferable that a layer contains the compound represented by General formula (1) individually or as a component of a mixture.

  According to such an organic electroluminescent element, since the compound for an organic electroluminescent element is included, a sufficiently long driving life can be obtained.

  Moreover, the organic electroluminescent device according to the present invention is an organic electroluminescent device in which at least one organic layer including a luminescent layer is sandwiched between a pair of electrodes composed of an anode and a cathode. It is preferable to consist of a mixed layer of the compound represented by (1) and a triarylamine derivative.

  According to such an organic electroluminescent device, since the crystallinity of the compound for organic electroluminescent device is low, a stable amorphous mixed layer with the triarylamine derivative can be formed, and a sufficiently long driving life is achieved. Can be obtained.

  Further, the organic electroluminescent device according to the present invention is an organic electroluminescent device in which a plurality of organic layers including a hole injection layer are sandwiched between a pair of electrodes composed of an anode and a cathode. It is preferable to consist of a mixed layer of the compound represented by (1) and an electron acceptor compound.

  According to such an organic electroluminescent element, since the crystallinity of the compound for organic electroluminescent element is low, a stable amorphous mixed layer with the electron acceptor compound can be formed, and a sufficiently long driving life is obtained. Can be obtained.

  The organic electroluminescent device according to the present invention comprises a compound represented by the general formula (1) in the organic electroluminescent device in which a plurality of organic layers including a light emitting layer and a hole injection layer are sandwiched, The hole injection layer is preferably composed of a mixed layer of a compound represented by the general formula (1) and an electron acceptor compound.

  According to such an organic electroluminescent device, since the crystallinity of the compound for organic electroluminescent device is low, a stable amorphous light emitting layer and hole injection layer can be formed, and a sufficiently long driving life is obtained. It becomes possible.

It is a schematic cross section which shows an example of the organic electroluminescent element concerning this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

(Compound for organic electroluminescence device)
The compound for organic electroluminescent elements according to a preferred embodiment of the present invention is an anthracene compound having a specific structure represented by the following general formula (1).

［式中、Ｘ_１〜Ｘ_１０のうち少なくとも１つは下記一般式（２）で表される。

[Wherein, at least one of X _{1 to} X ₁₀ is represented by the following general formula (2).

（式中、Ｌは連結基であり、位置１〜１４のいずれかの位置と連結する。なお、式中の番号は、連結基Ｌの連結位置を示すための番号である。連結されなかった位置１〜１４は、水素原子、置換または無置換のアルキル基、置換もしくは無置換のアリール基、置換もしくは無置換の複素環基のいずれかで置換される。Ｌは、単結合、置換もしくは無置換のアルキリレン基、置換もしくは無置換のアリーレン基、置換もしくは無置換の複素環骨格を有する２価の基のいずれかを示す。Ｒ_１およびＲ_２は、それぞれ独立に、水素原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアリール基のいずれかを示す。）Ｘ_１〜Ｘ_１０のうち一般式（２）でないものは、それぞれ独立に、水素原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアリール基、置換もしくは無置換の複素環基のいずれかを示す。］

(In the formula, L is a linking group and is linked to any one of positions 1 to 14. The number in the formula is a number for indicating the linking position of the linking group L. Not linked. Positions 1 to 14 are substituted with any of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group, and L is a single bond, substituted or unsubstituted. R ₁ and R ₂ are each independently a hydrogen atom, substituted or unsubstituted, a substituted alkylylene group, a substituted or unsubstituted arylene group, or a divalent group having a substituted or unsubstituted heterocyclic skeleton. A substituted alkyl group or a substituted or unsubstituted aryl group.) Among X _{1 to} X ₁₀ , those not represented by the general formula (2) are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, Place Or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. ]

The alkyl group in the general formula (1) is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, an n- or i-propyl group, n -, I-, s- or t-butyl group and the like can be mentioned.
The alkyl group may have a substituent, and examples of such a substituent include an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a halogeno group, and a silyl group.

The aryl group in the general formula (1) may be monocyclic or polycyclic, and includes condensed rings and ring assemblies. As such an aryl group, those having 6 to 20 carbon atoms are preferable, and specifically, phenyl group, naphthyl group, anthryl group, phenanthryl group, pyrenyl group, perylenyl group, fluorenyl group, o-, m- Or a p-biphenylyl group etc. are mentioned, Especially preferably, a phenyl group, a naphthyl group, and a biphenylyl group are mentioned.
The aryl group may be further substituted, and examples of such a substituent include an alkyl group, an alkoxy group, an aryl group, a heterocyclic group, an aryloxy group, a halogeno group, and a silyl group.

  As the heterocyclic group in the general formula (1), a 5- or 6-membered aromatic heterocyclic group containing O, N, S as a hetero atom, and a condensed polycyclic aromatic heterocyclic ring having 2 to 20 carbon atoms Groups and the like. Examples of the aromatic heterocyclic group and the condensed polycyclic aromatic heterocyclic group include a thienyl group, a furyl group, a pyrrolyl group, a pyridyl group, a quinolyl group, and a quinoxalyl group. These heterocyclic groups may be further substituted, and examples of such a substituent include an alkyl group, an alkoxy group, an aryl group, a heterocyclic group, an aryloxy group, and a halogeno group.

In the compound for organic electroluminescence device according to the present embodiment, X ₉ and X ₁₀ are each independently represented by the following formula (1) because the chemical stability and luminous efficiency of the compound can be improved. It is preferably a substituted or unsubstituted aryl group or a substituted or unsubstituted aromatic heterocyclic group.

In general formula (1), at least one of X _{1 to} X ₁₀ represents a group represented by general formula (2). From the viewpoint of sublimation purification and thermal stability during the vapor deposition process, X ₁ to X ₁₀ it is preferable 1-3 of ₁₀ is a group represented by the general formula (2).

In general formula (1), it is preferable that at least one of X ₂ , X ₃ , X ₆ , X ₇ , X ₉ and X ₁₀ represents a group represented by general formula (2).
In general formula (1), X ₂ and X ₉ preferably represent a group represented by general formula (2).
In general formula (1), X ₉ and X ₁₀ preferably represent a group represented by general formula (2).
In general formula (1), X ₉ preferably represents a group represented by general formula (2).
By substituting the group represented by the general formula (2) at these positions, the chemical stability of the compound of the general formula (1) can be improved, and the crystallinity of the molecule is reduced. This is because a stable amorphous film can be formed. As a result, when used as a compound for an organic electroluminescence device, a sufficiently long driving life can be realized.

From the viewpoint of the stability of the organic electroluminescent device, in general formula (1), those which are not general formula (2) among X _{1 to} X ₁₀ are independently a hydrogen atom, an alkyl group, a substituent or an unsubstituted group. An aryl group, a substituted or unsubstituted aromatic heterocyclic group is preferable.

From the viewpoint of ease of synthesis, in general formula (1), X ₁ , X ₄ , X ₅ and X ₈ are preferably hydrogen atoms.

  In general formula (2), L may be a substituted or unsubstituted alkylylene group. Specific examples of such an alkylylene period include a methylene group and an ethylene group.

In general formula (2), L may be a substituted or unsubstituted arylene group. Specific examples of such an arylene group include those in which two or more arylene groups are directly linked in addition to a normal arylene group such as a phenylene group, a biphenylene group, and an anthrylene group. The arylene group of the linking group L may be one in which two or more arylene groups are linked via an alkylene group, —O— or —S—.
The arylene group may be further substituted, and examples of such a substituent include an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a halogeno group, and a silyl group.

In general formula (2), L may be a divalent group having a substituted or unsubstituted heterocyclic skeleton. Examples of the divalent group having such a heterocyclic skeleton include 5-membered or 6-membered aromatic heterocyclic groups containing O, N, and S as heteroatoms, and condensed polycyclic aromatics having 2 to 20 carbon atoms. Specific examples include a heterocyclic group, and specific examples include a thienyl group, a furyl group, a pyrrolyl group, a pyridyl group, a quinolyl group, and a quinoxalyl group.
These heterocyclic groups may be further substituted, and examples of such substituents include alkyl groups, alkoxy groups, aryl groups, aryloxy groups, and halogeno groups.

Specific examples of L are shown in the following formulas (i-1) to (i-33), but the present embodiment is not limited to these.

  From the viewpoint of the stability of the compound and the organic electroluminescent device, in general formula (2), the linking group L is preferably a single bond or a substituted or unsubstituted arylene group.

  From the viewpoint of ease of synthesis, in the general formula (2), the linking group L is preferably substituted at any one of the positions 1, 2, and 4, and the positions 1 to 14 that are not linked to L are It is preferably substituted with a hydrogen atom.

From the viewpoint of ease of synthesis and stability of the compound, in general formula (2), R ₁ and R ₂ are each independently a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Preferably there is.

  There is no particular limitation on the molecular weight of the compound of the present embodiment, but it is preferable that the molecular weight is 1300 or less in consideration of the device preparation process. This is because a compound having a molecular weight of 1300 or more is difficult to synthesize due to a decrease in solubility, and it is difficult to produce an organic electroluminescent device by a coating process. In addition, even when an organic electroluminescent element is produced by a vapor deposition process, the vapor deposition temperature becomes a high temperature of 450 ° C. or more, which may cause decomposition of the material.

(Specific examples of compounds for organic electroluminescence devices)
As a suitable example of the compound for organic electroluminescent elements of this embodiment, following formula (I-1)-(I-20), (II-1)-(II-20), (III-1)-( And a compound represented by III-13).

(Organic electroluminescence device)
FIG. 1 is a schematic cross-sectional view showing an example of an organic electroluminescent element according to this embodiment. The organic electroluminescent element 1 shown in FIG. 1 includes a hole injection layer 4, a hole transport layer 5, a light emitting layer 6, and two electrodes (first electrode 3 and second electrode 9) arranged to face each other. The electron transport layer 7 and the electron injection layer 8 are sandwiched. The hole injection layer 4, the hole transport layer 5, the light emitting layer 6, the electron transport layer 7, and the electron injection layer 8 are all organic layers, and are stacked in this order from the first electrode 3 side. The electron injection layer 8 may be an inorganic layer (metal layer, metal compound layer, etc.).

  In the present embodiment, the first electrode 3 is formed on the substrate 2, but the order of stacking from the substrate 2 side may be reversed. That is, even if the second electrode 9, the electron injection layer 8, the electron transport layer 7, the light emitting layer 6, the hole transport layer 5, the hole injection layer 4, and the first electrode 3 are stacked in this order from the substrate 2 side. Good.

  In addition, the organic electroluminescent element compound of this embodiment may be contained in any of the above-described layers, but is desirably contained in the light emitting layer, the hole injection layer, and the electron transport layer.

  In the present embodiment, the first electrode 3 and the second electrode 9 function as a hole injecting electrode (anode) and an electron injecting electrode (cathode), respectively. Then, holes are injected from the second electrode 9 and electrons are injected from the second electrode 9. Based on these recombination, the compound for an organic electroluminescent element in the light emitting layer emits light.

  The preferred thicknesses of the hole injection layer 4, the hole transport layer 5, the light emitting layer 6, the electron transport layer 7 and the electron injection layer 8 are all 1 to 200 nm.

(substrate)
The substrate 2 can be used without particular limitation as long as it is provided in a conventional organic electroluminescence device, and is an amorphous substrate such as glass or quartz, Si, GaAs, ZnSe, ZnS, GaP. A crystal substrate such as InP or a metal substrate such as Mo, Al, Pt, Ir, Au, Pd, or SUS can be used. Alternatively, a thin film made of crystalline or amorphous ceramic, metal, organic material or the like formed on a predetermined substrate may be used.

  When the side of the substrate 2 is the light extraction side, it is preferable to use a transparent substrate such as glass or quartz as the substrate 2, and it is particularly preferable to use an inexpensive glass transparent substrate. The transparent substrate may be provided with a color filter film, a color conversion film containing a fluorescent material, a dielectric reflection film, or the like for adjusting the emission color.

(First electrode)
The first electrode 3 functions as a hole injection electrode (anode). Therefore, the material of the first electrode 3 can be used without particular limitation as long as it is provided in the conventional organic electroluminescent element, but it can be used efficiently and uniformly for the first electrode 3. A material capable of applying an electric field to is preferable.

  Further, when the substrate 2 side is the light extraction side, the transmittance at a wavelength of 400 nm to 700 nm, which is the emission wavelength region of the organic electroluminescent element, in particular, the transmittance of the first electrode 3 at the wavelength of each RGB color is 50%. Preferably, it is 80% or more, more preferably 90% or more. When the transmittance of the first electrode 3 is less than 50%, the light emission from the light emitting layer 6 is attenuated, and the luminance necessary for image display cannot be obtained.

The 1st electrode 3 with high light transmittance can be comprised using the transparent conductive film comprised with various oxides. As such a material, indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), zinc oxide (ZnO), tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), and the like are preferable. It is particularly preferable in that a thin film having a uniform in-plane specific resistance can be easily obtained.

  The film thickness of the first electrode 3 is preferably determined in consideration of the above-described light transmittance. For example, when using an oxide transparent electrode, the film thickness is preferably 10 to 500 nm, more preferably 30 to 300 nm. When the film thickness of the first electrode 3 exceeds 500 nm, the light transmittance becomes insufficient and the first electrode 3 may be peeled off from the substrate 2 in some cases. In addition, the light transmittance is improved as the film thickness is decreased. However, when the film thickness is less than 10 nm, the resistance increases and the driving voltage of the organic electroluminescent element tends to increase.

(Second electrode)
The second electrode 9 functions as an electron injection electrode (cathode). The material of the second electrode 9 can be used without particular limitation as long as it is provided in a conventional organic electroluminescent device, and examples thereof include metal materials, organometallic complexes, and metal compounds. In order to efficiently and reliably inject electrons into the light emitting layer 6, it is preferable to use a material having a relatively low work function, and it may be transparent.

  Specific examples of the metal material constituting the second electrode 9 include alkali metals such as Li, Na, K or Cs, alkaline earth metals such as Mg, Ca, Sr or Ba, or Al (aluminum). . Alternatively, a metal having properties similar to those of an alkali metal or alkaline earth metal such as La, Ce, Sn, Zn, or Zr can be used. Furthermore, oxides or halides of the above metal materials can also be used. Further, it may be a mixture or alloy containing the above materials, and a plurality of these may be laminated.

  The film thickness of the second electrode 9 may be such that electrons can be uniformly injected, and may be 0.1 nm or more.

  An auxiliary electrode may be provided on the second electrode 9. Thereby, the electron injection efficiency to the light emitting layer 6 can be improved, and the penetration | invasion of the water | moisture content or the organic solvent to the electron injection layer 8, the electron carrying layer 7, and the light emitting layer 6 can be prevented. As a material for the auxiliary electrode, a general metal can be used because there is no restriction on work function and charge injection capability. However, it is preferable to use a metal having high conductivity and easy handling. In particular, when the second electrode 9 includes an organic material, it is preferable to select appropriately according to the type and adhesion of the organic material.

  Examples of the material used for the auxiliary electrode include Al, Ag, In, Ti, Cu, Au, Mo, W, Pt, Pd, and Ni. Among them, by using a low-resistance metal such as Al and Ag. Electron injection efficiency can be further increased. Further, by using a metal compound such as TiN, higher sealing properties can be obtained. These materials may be used alone or in combination of two or more. Moreover, when using 2 or more types of metals, you may use as an alloy. Such an auxiliary electrode can be formed by, for example, a vacuum deposition method or the like.

(Hole injection layer)
The hole injection layer 4 is a layer containing a compound having a function of facilitating the injection of holes from the first electrode 3. Specifically, it can be formed using at least one kind of arylamine, phthalocyanine, polyaniline / organic acid, polythiophene / polymer acid and the like. Since the compound represented by the general formula (1) according to the present embodiment has a work function larger than that of the first electrode 3, the compound is usually not suitable for the hole injection layer 4. However, when holes are forcibly generated using an electron acceptor such as antimony chloride, iron chloride, or molybdenum oxide, hole injection from the first electrode 3 becomes easy. The compound represented by the general formula (1) according to the form can be used as the hole injection layer 4. In particular, since the compound represented by the general formula (1) has low crystallinity, a stable amorphous mixed layer with an electron acceptor compound can be formed, and a sufficiently long luminance half-life can be obtained. It becomes possible.

(Hall transport layer)
The hole transport layer 5 is a layer containing a compound having a function of transporting injected holes (holes) to the light emitting layer 6 and a function of preventing electrons in the light emitting layer 6 from being injected into the hole transport layer 5. It is. The hole transport layer 5 uses at least one kind of hydrocarbon compound such as triarylmethane derivative, triarylamine derivative, stilbene derivative, polysilane derivative, polyphenylene vinylene and derivative thereof, polythiophene and derivative thereof, carbazole derivative or anthracene derivative. Can be formed. Further, the compound represented by the general formula (1) according to this embodiment can also be used as the hole transport layer 5.

  In addition, if it is a material which has the function of the hole injection layer 4 and the hole transport layer 5 as a hole injection transport layer, it can fulfill the function for two layers by a single layer. On the other hand, the hole injection layer 4 and the hole transport layer 5 can be further functionally separated into a plurality of layers.

(Light emitting layer)
The light emitting layer 6 is a layer containing a compound having a function of transporting injected holes and electrons and a function of generating excitons by recombination of holes and holes. Hydrocarbon compounds such as naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, fluoranthene derivatives and naphthacene derivatives are preferably used. The compound represented by the general formula (1) according to this embodiment is preferably used for the light emitting layer 6 and is usually used as a host material. Since the compound represented by the general formula (1) has low crystallinity and can form a stable amorphous film, a sufficiently long luminance half-life is obtained as compared with a conventional organic electroluminescent device. It becomes possible.

  In addition to the host material, the light emitting layer 6 may contain another fluorescent substance as a light emitting doping material. Examples of the fluorescent substance include compounds such as quinacridone, rubrene, and styryl dyes, metal complex compounds having 8-quinolinol or a derivative thereof such as tris (8-quinolinolato) aluminum as a ligand, tetraphenylbutadiene, anthracene, Fluoranthene, pyrene, perylene, coronene, 12-phthaloperinone derivatives, phenylanthracene derivatives, tetraarylethene derivatives, aromatic amine derivatives, and the like can be given. In particular, aromatic amine derivatives such as aminonaphthalene derivatives, aminopyrene derivatives, aminophenanthrene derivatives, aminofluorene derivatives, aminochrysene derivatives, aminoanthracene derivatives, and aminoperylene derivatives are very preferable materials. Although suitable content of dopant material changes with combinations of host material and dopant material, it is preferable that it is 0.1-30 mass% on the basis of the whole constituent material of a light emitting layer, and it is 1-10 mass% Is more preferable.

  The light emitting layer 6 may contain other compounds of the host material and the light emitting doping material. By mixing other compounds, carrier transport can be adjusted, and by mixing fluorescent dyes, the emission color can be converted and used. Examples of the compound for adjusting carrier transport include metal complex compounds having 8-quinolinol or a derivative thereof such as tris (8-quinolinolato) aluminum as a ligand, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, imidazopyridine derivatives, Electron transporting compounds such as imidazopyrimidine derivatives and phenanthroline derivatives, hole transporting compounds such as triarylamine derivatives, and the like can be preferably used. Since the compound represented by the general formula (1) according to the present embodiment has low crystallinity, it can form a stable amorphous mixed layer with an electron transporting compound or a hole transporting compound. It is possible to obtain a long driving life.

(Electron transport layer)
The electron transport layer 7 has a function of transporting injected electrons and a function of preventing holes from being injected into the electron transport layer 7 from the light emitting layer 6. The compound represented by the general formula (1) of the present embodiment can be used as the electron transport layer 7, and particularly when the compound represented by the general formula (1) is used for the light emitting layer, Since the electron injection efficiency is good, it is preferable to use the same material as the light emitting layer for the electron transport layer.

(Electron injection layer)
The electron injection layer 8 has a function of facilitating injection of electrons from the second electrode 9 and a function of improving adhesion with the second electrode 9. The electron injection layer 8 is composed of a metal complex, an oxadiazole derivative, a triazole derivative, a triazine derivative, a quinoline derivative, a quinoxaline derivative, diphenylquinone having an 8-quinolinol or its derivative such as tris (8-quinolinolato) aluminum as a ligand. Derivatives, nitro-substituted fluorenone derivatives, thiopyrandioxide derivatives, pyridine derivatives, pyrimidine derivatives, imidazopyridine derivatives, imidazopyrimidine derivatives, phenanthroline derivatives, and the like can be used.

  The organic electroluminescence device 1 according to this embodiment is known except that the light emitting layer 6, the hole injection layer 4, the hole transport layer 5, and the electron transport layer 7 contain the compound for an organic electroluminescence device according to this embodiment. It can manufacture by the method of. As a method of forming each organic layer including the light emitting layer 6, the hole injection layer 4, the hole transport layer 5, and the electron transport layer 7, a vacuum deposition method, an ionization deposition method, a coating method, etc. are used. Depending on the material to be configured, it can be selected and adopted as appropriate.

  Specific examples of the coating method include spin coating methods, various printing methods such as gravure printing, and ink jet methods. Examples of the solvent used in this coating method include hydrocarbon solvents such as toluene and xylene, and halogen solvents such as dichloroethane. The compound represented by the general formula (1) according to this embodiment has high solubility because of low symmetry, and can be sufficiently formed even by a coating process. In the case of the spin coating method, a thin film of about 50 nm to 200 nm can be formed by using a solution having a concentration of about 1 to 3%.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  Hereinafter, the contents of the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited to the following Example.

<Synthesis Example 1>
The following compound (11) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of Compound (1-1))
Under argon stream, methyl 1-bromonaphthalene-2-carboxylate 16.28 g (61.4 mmol), 9-phenanthreneboronic acid 15.00 g (67.5 mmol), tetrakis (triphenylphosphine) palladium (0) 1.42 g (1.23 mmol) was dissolved in 110 ml of toluene and 40 ml of ethanol. Next, 92 ml of an aqueous solution containing 184.0 mmol of sodium carbonate was added, and the mixture was stirred for 19 hours under reflux with heating. After cooling to room temperature, water was added to the reaction solution and extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography to obtain the target compound (1-1) white solid (yield 22.03 g, yield 99%).

(Synthesis of Compound (1-2))
Under an argon stream, 180 ml of a dehydrated tetrahydrofuran solution containing 22.03 g (61.0 mmol) of the compound (1-1) synthesized by the above reaction was added to 90 ml of a dehydrated diethyl ether solution containing 180.0 mmol of methyl magnesium iodide over 30 minutes. The solution was added dropwise and stirred at room temperature for 22 hours. A saturated aqueous ammonium chloride solution was added to the reaction solution, and the mixture was extracted with diethyl ether. The organic layer was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The obtained crude product was purified by column chromatography to obtain a white solid (yield 17.25 g, yield 78%) of the target compound (1-2).

(Synthesis of Compound (1-3))
Under an argon stream, 17.25 g (50.0 mmol) of the compound (1-2) synthesized by the above reaction was dissolved in 150 ml of dehydrated dichloromethane and cooled in an ice bath. 9.3 ml (75.0 mmol) of boron trifluoride diethyl ether complex was added dropwise over 10 minutes, and then stirred at room temperature for 17 hours. Water was added to the reaction solution and extracted with dichloromethane. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography to obtain the target compound (1-3) as a white solid (yield 16.71 g, yield 97%).

(Synthesis of Compound (1-4))
Under an argon stream, 16.71 g (48.5 mmol) of the compound (1-3) synthesized by the above reaction was dissolved in 300 ml of dehydrated dichloromethane and cooled in an ice bath. N-bromosuccinimide (8.63 g, 48.5 mmol) was slowly added, followed by stirring at room temperature for 16 hours. Water was added to the reaction solution and extracted with dichloromethane. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography to obtain a white powder (yield 18.48 g, yield 90%) of the target compound (1-4).

(Synthesis of Compound (1-5))
4.23 g (10.0 mmol) of compound (1-4) synthesized by the above reaction under an argon stream, 3.81 g (15.0 mmol) of bis (pinacolato) diboron, tris (dibenzylideneacetone) dipalladium (0) 0.092 g (0.10 mmol), 2-dicyclohexylphosphino-2 ′, 4 ′, 6′-triisopropylbiphenyl 0.095 g (0.20 mmol), potassium acetate 2.94 g (30.0 mmol) were dehydrated 1, The mixture was dissolved in 30 ml of 4-dioxane and stirred for 21 hours while heating under reflux. After cooling to room temperature, the mixture was concentrated under reduced pressure, water was added, and the mixture was extracted with chloroform. The organic layer was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and then recrystallized from dichloromethane-hexane to obtain a white powder (4.33 g, yield 92%) of the desired compound (1-5).

(Synthesis of Compound (1-6))
Under an argon stream, 9.43 g (21.0 mmol) of 9-bromoanthracene, 4.75 g (24.0 mmol) of 4-biphenylboronic acid, 0.090 g (0.40 mmol) of palladium (0) acetate, 0.03 g of triphenylphosphine. 21 g (0.80 mmol) was dissolved in 80 ml of ethylene glycol dimethyl ether. Next, 30 ml of an aqueous solution containing 60.0 mmol of potassium carbonate was added, and the mixture was stirred for 17 hours while heating under reflux. After cooling to room temperature, the mixture was concentrated under reduced pressure, methanol and water were added, and the precipitated solid was filtered. The obtained solid was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the target compound (1-6) as a white solid (yield 7.00 g, yield 99%).

(Synthesis of Compound (1-7))
Under an argon stream, 7.00 g (21.0 mmol) of the compound (1-6) synthesized by the above reaction was dissolved in 150 ml of dehydrated dimethylformamide and cooled in an ice bath. 20 ml of a dehydrated dimethylformamide solution containing 25.4 mmol of N-bromosuccinimide was added dropwise over 10 minutes, and then stirred at room temperature for 16 hours. Water and methanol were added to the reaction solution, and the precipitated solid was filtered and washed with methanol. The obtained solid was dried under reduced pressure to obtain a white powder (yield: 8.25 g, yield: 95%) of the target compound (1-7).

(Synthesis of Compound (11))
1.10 g (2.36 mmol) of compound (1-5) synthesized by the above reaction under an argon stream, 0.819 g (2.00 mmol) of compound (1-7), 0.009 g (0) of palladium acetate (0) 0.04 g), 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl 0.033 g (0.08 mmol), and potassium phosphate tribasic acid 0.849 g (4.00 mmol) in 20 ml toluene and 0.5 ml water. It was dissolved and stirred for 22 hours under heating to reflux. After cooling to room temperature, the mixture was concentrated under reduced pressure, water was added, and the mixture was extracted with chloroform. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and then recrystallized from dichloromethane / methanol to obtain the target compound (11) as a white powder (yield 1.00 g, yield 74%). Furthermore, sublimation purification was performed to obtain a product having a purity of 99.8% (confirmed by high performance liquid chromatography (HPLC)).

Note that, when mass analysis of the obtained compound was performed, a peak was confirmed at m / z = 672 (M ⁺ ) with respect to the molecular weight 672 of the compound (11), and the compound obtained in Synthesis Example 1 was found to be the compound ( 11).

<Synthesis Example 2>
The following compound (12) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of Compound (1-8))
Under an argon stream, 9-bromoanthracene 25.53 g (99.3 mmol), phenylboronic acid 14.51 g (119.0 mmol), palladium acetate (0) 0.45 g (2.0 mmol), triphenylphosphine 1.05 g ( 4.0 mmol) was dissolved in 400 ml of ethylene glycol dimethyl ether. Next, 150 ml of an aqueous solution containing 300.0 mmol of potassium carbonate was added, and the mixture was stirred for 17 hours while heating under reflux. After cooling to room temperature, the mixture was concentrated under reduced pressure, methanol and water were added, and the precipitated solid was filtered. The obtained solid was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the target compound (1-8) as a white solid (yield 24.58 g, yield 97%).

(Synthesis of Compound (1-9))
Under an argon stream, 24.58 g (96.7 mmol) of the compound (1-8) synthesized by the above reaction was dissolved in 500 ml of dehydrated dimethylformamide and cooled in an ice bath. 100 ml of a dehydrated dimethylformamide solution containing 106.4 mmol of N-bromosuccinimide was added dropwise over 1 hour, followed by stirring at room temperature for 18 hours. Water and methanol were added to the reaction solution, and the precipitated solid was filtered and washed with methanol. The obtained solid was dried under reduced pressure to obtain a white powder (yield 30.26 g, yield 94%) of the target compound (1-9).

(Synthesis of Compound (1-10))
Under an argon stream, 9.99 g (30.0 mmol) of the compound (1-9) synthesized by the above reaction was dissolved in 200 ml of dehydrated tetrahydrofuran and cooled to -78 ° C. 21 ml of dehydrated hexane solution containing 33.0 mmol of n-butyllithium was added dropwise over 20 minutes, and then stirred at -78 ° C for 1 hour. 9.0 ml (39.0 mmol) of triisopropyl borate was added dropwise over 5 minutes, stirred at −78 ° C. for 1 hour, and then stirred at room temperature for 2 hours. The reaction solution was cooled in an ice bath, diluted hydrochloric acid was added, and the mixture was stirred for 30 minutes and extracted with diethyl ether. The organic layer was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The resulting compositional organism was washed with diethyl ether to obtain the target compound (1-10) white powder (yield 7.04 g, yield 79%).

(Synthesis of Compound (1-11))
3.58 g (12.0 mmol) of compound (1-10) synthesized by the above reaction under an argon stream, 11.32 g (48.0 mmol) of 1,4-dibromobenzene, tetrakis (triphenylphosphine) palladium (0) 0.28 g (0.24 mmol) was dissolved in 80 ml of toluene and 10 ml of ethanol. Next, 18 ml of an aqueous solution containing 36.0 mmol of sodium carbonate was added, and the mixture was stirred for 18 hours while heating under reflux. After cooling to room temperature, water was added to the reaction solution and extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography to obtain the target compound (1-11) as a white solid (yield 2.50 g, yield 51%).

(Synthesis of Compound (12))
1.087 g (2.31 mmol) of the compound (1-5) synthesized by the above reaction under an argon stream, 0.818 g (2.00 mmol) of the compound (1-11), 0.009 g (0) of palladium acetate (0) 0.04 g), 0.033 g (0.08 mmol) of 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl and 0.849 g (4.00 mmol) of potassium phosphate tribasic acid in 15 ml of toluene and 0.5 ml of water. Dissolved and stirred for 16 hours under reflux with heating. After cooling to room temperature, the mixture was concentrated under reduced pressure, water was added, and the mixture was extracted with chloroform. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and recrystallized from dichloromethane-methanol and toluene to obtain a white powder (yield 1.21 g, yield 90%) of the target compound (12). Furthermore, sublimation purification was performed to obtain a product having a purity of 99.8% (confirmed by high performance liquid chromatography (HPLC)).

Note that, when mass analysis of the obtained compound was performed, a peak was confirmed at m / z = 672 (M ⁺ ) with respect to the molecular weight 672 of the compound (12), and the compound obtained in Synthesis Example 2 was found to be the compound ( 12).

<Synthesis Example 3>
The following compound (13) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of Compound (1-12))
3.26 g (10.9 mmol) of compound (1-10) synthesized by the above reaction under an argon stream, 6.6 ml (54.8 mmol) of 1,3-dibromobenzene, tetrakis (triphenylphosphine) palladium (0) 0.25 g (0.22 mmol) was dissolved in 60 ml of toluene and 8 ml of ethanol. Next, 17 ml of an aqueous solution containing 34.0 mmol of sodium carbonate was added, and the mixture was stirred for 16 hours under reflux with heating. After cooling to room temperature, water was added to the reaction solution and extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography to obtain the target compound (1-12) as a white solid (yield 2.92 g, yield 65%).

(Synthesis of Compound (13))
1.76 g (3.75 mmol) of compound (1-5) synthesized by the above reaction under argon stream, 1.28 g (3.13 mmol) of compound (1-12), 0.014 g (0) of palladium acetate (0) 0.06 mmol), 0.049 g (0.12 mmol) of 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl and 1.32 g (6.26 mmol) of potassium phosphate tribasic acid in 15 ml of toluene and 0.5 ml of water. Dissolved and stirred for 16 hours under reflux with heating. After cooling to room temperature, the mixture was concentrated under reduced pressure, water was added, and the mixture was extracted with chloroform. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and then recrystallized from dichloromethane-methanol and toluene-methanol to obtain a white powder (yield 1.56 g, yield 74%) of the desired compound (13). Furthermore, sublimation purification was performed to obtain a product having a purity of 99.9% (purity confirmed by high performance liquid chromatography (HPLC)).

Note that, when mass analysis of the obtained compound was performed, a peak was confirmed at m / z = 672 (M ⁺ ) with respect to the molecular weight 672 of the compound (13), and the compound obtained in Synthesis Example 3 was found to be the compound ( 13).

<Synthesis Example 4>
The following compound (14) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of Compound (14))
2.07 g (4.40 mmol) of the compound (1-5) synthesized by the above reaction under an argon stream, 0.67 g (2.00 mmol) of 9,10-dibromoanthracene, 0.018 g (0) of palladium acetate (0) 0.08 mmol), 0.066 g (0.16 mmol) of 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl, 1.69 g (8.00 mmol) of potassium phosphate tribasic acid in 20 ml of toluene and 0.5 ml of water. It was dissolved and stirred for 53 hours under heating to reflux. After cooling to room temperature, the mixture was extracted with chloroform using a Soxhlet extractor. The obtained crude product was washed with chloroform to obtain a white powder (yield 0.83 g, yield 48%) of the target compound (14). Furthermore, sublimation purification was performed to obtain a 99.6% pure product (purity confirmed by high performance liquid chromatography (HPLC)).

Note that, when mass analysis of the obtained compound was performed, a peak was confirmed at m / z = 863 (M ⁺ ) with respect to the molecular weight 863 of the compound (14), and the compound obtained in Synthesis Example 4 was found to be the compound ( 14).

<Example 1>
An ITO transparent electrode having a thickness of 100 nm was formed on a glass substrate by RF sputtering and patterned. This glass substrate with an ITO transparent electrode was subjected to ultrasonic cleaning using a neutral detergent, acetone and ethanol, and then pulled up from boiling ethanol and dried. After the surface of the transparent electrode was washed with UV / O _3, it was fixed to a substrate holder of a vacuum deposition apparatus, and the inside of the layer was depressurized to 1 × 10 ⁻⁴ Pa or less.

Next, while maintaining the reduced pressure state, N, N′-diphenyl-N, N′— having the following structure:
Bis [N- (4-methylphenyl) -N-phenyl- (4-aminophenyl)]-1,1
50 nm of '-biphenyl-4,4'-diamine (21) at a deposition rate of 0.1 nm / sec.
The hole injection layer was formed as a hole injection layer.

  Next, N, N, N ′, N′-tetrakis (3-biphenylyl) -1,1′-biphenyl-4,4′-diamine (22) having the following structure was deposited while maintaining the reduced pressure state. Vapor deposition was performed at a thickness of 80 nm at 0.1 nm / sec to form a hole transport layer.

  Further, while maintaining the reduced pressure state, the compound (11) of the present embodiment as a host material and the compound (23) having the following structure as a dopant at a mass ratio of 97: 3 and an overall deposition rate of 0.1 nm / The light emitting layer was formed by vapor deposition to a thickness of 40 nm as sec.

Further, while maintaining the reduced pressure state, the compound (11) of this embodiment is successively deposited to a thickness of 20 nm at a deposition rate of 0.1 nm / sec, and Alq ₃ is successively deposited to a thickness of 10 nm at a deposition rate of 0.1 nm / sec. It vapor-deposited and was set as the electron injection transport layer.

  Next, LiF is deposited at a deposition rate of 0.1 nm / sec to a thickness of 0.5 nm, used as an electron injection electrode, Al is deposited as a protective electrode to a thickness of 100 nm, and finally glass sealed to organic electroluminescence. An element was obtained. The sublimation purification of the compound (11) can be performed at any stage as long as it is before vapor deposition.

When a direct current voltage was applied to the organic electroluminescence device, blue light emission derived from a light emitting dopant having an initial luminance of 680 cd / m ² and a luminance half life of 5000 hours was obtained at a current density of 10 mA / cm ² .

<Examples 2-28 and Comparative Examples 1-3>
An organic electroluminescent device was produced in the same manner as in Example 1 except that the compounds listed in Table 1 were used instead of the compound (11). Table 1 shows the luminance half-life time and initial luminance of these elements. The compound used for the comparative example has the structure shown below.

  According to Examples 1 to 28 and Comparative Examples 1 to 3, the organic electroluminescent elements in which the compounds used in Examples 1 to 28 are contained in the organic layer are the comparative compounds (31), (32), and (33). It has been shown that a sufficiently long drive life can be obtained compared to the included organic electroluminescent device.

<Example 29>
An ITO transparent electrode having a thickness of 100 nm was formed on a glass substrate by RF sputtering and patterned. This glass substrate with an ITO transparent electrode was subjected to ultrasonic cleaning using a neutral detergent, acetone and ethanol, and then pulled up from boiling ethanol and dried. After the surface of the transparent electrode was washed with UV / O _3, it was fixed to a substrate holder of a vacuum deposition apparatus, and the inside of the layer was depressurized to 1 × 10 ⁻⁴ Pa or less.

  Next, while maintaining the reduced pressure state, the compound (21) was deposited at a deposition rate of 0.1 nm / sec to a thickness of 50 nm to form a hole injection layer.

  Next, while maintaining the reduced pressure state, the compound (22) was deposited to a thickness of 80 nm at a deposition rate of 0.1 nm / sec to form a hole transport layer.

  Furthermore, while maintaining the reduced pressure state, the compound (11), the compound (22) of the present embodiment as the host material, and the compound (23) as the dopant in a volume ratio of 87: 10: 3, with an overall deposition rate of 0.8. Vapor deposition was performed at a thickness of 40 nm at 1 nm / sec to obtain a light emitting layer.

Further, while maintaining the reduced pressure state, the compound (11) of this embodiment is successively deposited to a thickness of 20 nm at a deposition rate of 0.1 nm / sec, and Alq ₃ is successively deposited to a thickness of 10 nm at a deposition rate of 0.1 nm / sec. It vapor-deposited and was set as the electron injection transport layer.

  Next, LiF is deposited at a deposition rate of 0.1 nm / sec to a thickness of 0.5 nm, used as an electron injection electrode, Al is deposited as a protective electrode to a thickness of 100 nm, and finally glass sealed to organic electroluminescence. An element was obtained.

When a direct current voltage was applied to the electroluminescent element, blue light emission derived from a light emitting dopant having an initial luminance of 640 cd / m ² and a luminance half life of 5400 hours was obtained at a current density of 10 mA / cm ² .

<Examples 30 to 36, Comparative Examples 4 to 6>
An electroluminescent device was produced in the same manner as in Example 29 except that the compounds listed in Table 2 were used instead of the compound (11). Table 2 shows the luminance half-life time and initial luminance of these elements.

  According to Examples 29 to 36 and Comparative Examples 4 to 6, the organic electroluminescent elements in which the compounds used in Examples 29 to 36 were included in the organic layer were obtained by comparing the comparative compounds (31), (32), and (33). It has been shown that a sufficiently long drive life can be obtained compared to the included organic electroluminescent device.

<Example 37>
An ITO transparent electrode having a thickness of 100 nm was formed on a glass substrate by RF sputtering and patterned. This glass substrate with an ITO transparent electrode was subjected to ultrasonic cleaning using a neutral detergent, acetone and ethanol, and then pulled up from boiling ethanol and dried. After the surface of the transparent electrode was washed with UV / O _3, it was fixed to a substrate holder of a vacuum deposition apparatus, and the inside of the layer was depressurized to 1 × 10 ⁻⁴ Pa or less.

  Next, while maintaining the reduced pressure state, the compound (11) of the present embodiment and molybdenum oxide were vapor-deposited at a volume ratio of 95: 5 to a film thickness of 50 nm at an overall vapor deposition rate of 0.1 nm / sec. It was.

  Next, while maintaining the reduced pressure state, the compound (11) of the present embodiment was deposited to a thickness of 80 nm at a deposition rate of 0.1 nm / sec to form a hole transport layer.

  Furthermore, while maintaining the reduced pressure state, the compound (11) of the present embodiment as the host material and the compound (23) as the dopant in a volume ratio of 97: 3 and a thickness of 40 nm at an overall deposition rate of 0.1 nm / sec. The light emitting layer was formed by vapor deposition.

Further, while maintaining the reduced pressure state, the compound (11) of this embodiment is successively deposited to a thickness of 20 nm at a deposition rate of 0.1 nm / sec, and Alq ₃ is successively deposited to a thickness of 10 nm at a deposition rate of 0.1 nm / sec. It vapor-deposited and was set as the electron injection transport layer.

  Next, LiF is deposited at a deposition rate of 0.1 nm / sec to a thickness of 0.5 nm, used as an electron injection electrode, Al is deposited as a protective electrode to a thickness of 100 nm, and finally glass sealed to organic electroluminescence. I got 6 children.

When a direct current voltage was applied to the electroluminescent element, blue light emission derived from a light emitting dopant having an initial luminance of 550 cd / m ² and a luminance half life of 4500 hours was obtained at a current density of 10 mA / cm ² .

<Examples 38 to 44, Comparative Examples 7 to 9>
An electroluminescent device was produced in the same manner as in Example 37 except that the compounds listed in Table 3 were used instead of the compound (11). Table 3 shows the luminance half-life time and initial luminance of these elements.

  According to Examples 37 to 44 and Comparative Examples 7 to 9, the organic electroluminescent devices in which the compounds used in Examples 37 to 44 were included in the organic layer were obtained by comparing the comparative compounds (31), (32), and (33). It has been shown that a sufficiently long drive life can be obtained compared to the included organic electroluminescent device.

<Example 45>
When the organic electroluminescent element produced in Example 1 was stored at 85 ° C. and the light emission state after 300 hours was confirmed, it showed blue-green uniform light emission, and no change was seen in the uniformity of the light emitting surface before and after heating. It was.

<Example 46>
When the organic electroluminescent element produced in Example 2 was stored at 85 ° C. and the light emission state after 300 hours was confirmed, it showed blue-green uniform light emission, and no change was seen in the uniformity of the light emitting surface before and after heating. It was.

<Example 47>
When the organic electroluminescent element produced in Example 3 was stored at 85 ° C. and the light emission state after 300 hours was confirmed, it showed blue-green uniform light emission, and no change was seen in the uniformity of the light emitting surface before and after heating. It was.

<Example 48>
When the organic electroluminescent element produced in Example 4 was stored at 85 ° C. and the light emitting state after 300 hours was confirmed, it showed blue-green uniform light emission, and no change was seen in the uniformity of the light emitting surface before and after heating. It was.

<Example 49>
The organic electroluminescent element produced in Example 37 was stored at 85 ° C., and the light emission state after 300 hours was confirmed. As a result, blue-green uniform light emission was shown, and there was no change in the uniformity of the light emitting surface before and after heating. It was.

<Example 50>
The organic electroluminescent element produced in Example 38 was stored at 85 ° C., and the light emission state after 300 hours was confirmed. As a result, blue-green uniform light emission was shown, and there was no change in the uniformity of the light emitting surface before and after heating. It was.

<Example 51>
The organic electroluminescent element produced in Example 39 was stored at 85 ° C., and the light emission state after 300 hours was confirmed. As a result, blue-green uniform light emission was shown, and there was no change in the uniformity of the light emitting surface before and after heating. It was.

<Example 52>
When the organic electroluminescent element produced in Example 40 was stored at 85 ° C. and the light emission state after 300 hours was confirmed, it showed blue-green uniform light emission, and there was no change in the uniformity of the light emitting surface before and after heating. It was.

<Comparative Example 10>
When the organic electroluminescent element produced in Comparative Example 1 was stored at 85 ° C. and the light emitting state after 300 hours was confirmed, a non-uniform light emitting surface was observed.

<Comparative Example 11>
When the organic electroluminescent element produced in Comparative Example 2 was stored at 85 ° C. and the light emitting state after 300 hours was confirmed, a non-uniform light emitting surface was observed.

<Comparative Example 12>
When the organic electroluminescent element produced in Comparative Example 3 was stored at 85 ° C. and the light emitting state after 300 hours was confirmed, a non-uniform light emitting surface was observed.

<Comparative Example 13>
When the organic electroluminescent element produced in Comparative Example 7 was stored at 85 ° C. and the light emitting state after 300 hours was confirmed, a non-uniform light emitting surface was observed.

<Comparative example 14>
When the organic electroluminescent element produced in Comparative Example 8 was stored at 85 ° C. and the light emitting state after 300 hours was confirmed, a non-uniform light emitting surface was observed.

<Comparative Example 15>
When the organic electroluminescent element produced in Comparative Example 9 was stored at 85 ° C. and the light emitting state after 300 hours was confirmed, a non-uniform light emitting surface was observed.

  According to Examples 45 to 52 and Comparative Examples 11 to 15, the compounds used in Examples 45 to 52 are low in crystallinity as compared with Comparative Compounds (31), (32), and (33). It has been shown that when a stable amorphous film is formed and used as a material for an organic electroluminescence device, a stable and uniform light emitting surface can be maintained even under high temperature storage. That is, since the organic electroluminescent element containing the compound used in Examples 45 to 52 in the organic layer can suppress heat generation due to driving and crystallization of the organic layer with time, the driving life is sufficiently long. Is obtained.

  As described in detail above, the compound for organic electroluminescence device of the present invention can realize an organic electroluminescence device having a sufficiently long driving life by containing it in the organic layer.

  DESCRIPTION OF SYMBOLS 1 ... Organic electroluminescent element concerning this embodiment, 2 ... Substrate, 3 ... 1st electrode, 4 ... Hole injection layer, 5 ... Hole transport layer, 6 ... Light emitting layer, 7 ... Electron transport layer, 8 ... Electron injection Layer, 9 ... second electrode, P ... power source.

Claims (5)

The compound for organic electroluminescent elements represented by following General formula (1).

[Wherein, at least one of X _{1 to} X ₁₀ is represented by the following general formula (2).

(In the formula, L is a linking group and is linked to any one of positions 1 to 14. The number in the formula is a number for indicating the linking position of the linking group L. Not linked. Positions 1 to 14 are substituted with any of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group, and L is a single bond, substituted or unsubstituted. R ₁ and R ₂ are each independently a hydrogen atom, substituted or unsubstituted, a substituted alkylylene group, a substituted or unsubstituted arylene group, or a divalent group having a substituted or unsubstituted heterocyclic skeleton. A substituted alkyl group or a substituted or unsubstituted aryl group.) Among X _{1 to} X ₁₀ , those not represented by the general formula (2) are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, Place Or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. ]   In the organic electroluminescent element in which at least one organic layer including a light emitting layer is sandwiched between a pair of electrodes composed of an anode and a cathode, at least one layer of the organic layer is a compound of claim 1 alone. Or it contains as a component of a mixture, The organic electroluminescent element characterized by the above-mentioned.   In the organic electroluminescence device in which at least one organic layer including a light emitting layer is sandwiched between a pair of electrodes composed of an anode and a cathode, the light emitting layer is formed by combining the compound according to claim 1 and a triarylamine derivative. An organic electroluminescent device comprising a mixed layer.   In the organic electroluminescent element in which a plurality of organic layers including a hole injection layer are sandwiched between a pair of electrodes composed of an anode and a cathode, the hole injection layer is a mixture of the compound according to claim 1 and an electron acceptor compound. An organic electroluminescence device comprising a layer.   In the organic electroluminescent element in which a plurality of organic layers including a light emitting layer and a hole injection layer are sandwiched between a pair of electrodes consisting of an anode and a cathode, the light emitting layer is made of the compound according to claim 1, and the hole 2. An organic electroluminescent device, wherein the injection layer comprises a mixed layer of the compound according to claim 1 and an electron acceptor compound.

Images